Vehicle step tube

ABSTRACT

A vehicle step tube comprising a one-piece elongated extrusion having a plurality of vertical ribs extending from the upper surface. The ribs are relatively short in a step portion of the extrusion to form a step platform. The ribs are relatively tall in the non-step portions flanking the step portion. The ribs define transverse recesses in the step portion to enhance traction and aesthetics.

BACKGROUND OF THE INVENTION

The present invention relates to step tubes for vehicles and to a methodfor making step tubes.

Step tubes, which are substitutes for running boards, are commonlymounted on vehicles for assisting a user of the vehicle to climb intoand out of the vehicle. They are also commonly used for aestheticreasons, and to protect the side of the vehicle.

Step tubes can be fabricated from aluminum extrusions. An example ofsuch a step tube is disclosed in U.S. Pat. No. 6,588,782 to Coomber. TheCoomber step tube includes an elongated support portion 100, multiplecap portions 200, a step pad 300, and a mounting bracket 400. The capportions 200 and the step portion 300 attach to the support portion 100to form an upper surface of the assembly that is aesthetically pleasingand functional for assisting vehicle users. The step portion 300 mayinclude a name plate 962, a plurality of perforations 964 to allowpassage of light through the step pad 300, and a plurality of ridges 972to provide traction for users stepping on the step portion 300.

The Coomber step tube requires a considerable fabrication and assemblyof multiple extruded components. Consequently, manufacture of theCoomber step tube requires significant labor and therefore expense.

SUMMARY OF THE INVENTION

The aforementioned problems are overcome by the present invention,wherein a step tube comprises a one-piece extrusion that includes aplurality of generally vertical ribs on its upper portion. The ribs varyin height along their longitudinal extent, with the ribs beingrelatively short in one or more step portions and relatively high in thenon-step portions flanking the step portion. The ribs provide tractionin the step portion.

In one embodiment, transition portions extend between the step portionand the non-step portions. The height of the ribs gradually transitionsfrom the high height in the non-step portions to the short height in thestep portion.

In another embodiment, the ribs in the step portion include transversecuts to further enhance traction and aesthetics in the step portion. Thecuts may be located at spaced intervals throughout the step portion.

The present invention also includes a method of manufacturing a steptube, comprising the steps of a) extruding an elongated beam having aplurality of vertically extending ribs and b) removing a portion of theribs in a step portion of the beam to define a step platform. Theremoving step may be performed by a computer operated machine.

The step tube of the present invention has a simplified unitaryconstruction. The step tube can be manufactured more simply and withlower cost than prior step tubes. Therefore, the step tube providesadvantages in manufacture and aesthetics without forfeiting function orstructure.

These and other objects, advantages, and features of the invention willbe more fully understood and appreciated by reference to the descriptionof the current embodiments and the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of the step tube and a vehicle body.

FIG. 2 is a perspective view of the step tube.

FIG. 3 is a perspective view of the step tube extrusion at section II inFIG. 1.

FIG. 4 is an end view of the extrusion of FIG. 2.

FIG. 5 is a perspective view of the extrusion at section II in FIG. 1,including a first cut.

FIG. 5A is a side view of the extrusion of FIG. 5.

FIG. 6 is a perspective view of the extrusion of FIG. 5, also includinga second cut.

FIG. 6A is a side view of the extrusion of FIG. 6.

FIG. 7 is a perspective view of a second embodiment of the extrusion atsection II of FIG. 1.

FIG. 8 is an end view of the extrusion of FIG. 7.

FIG. 9 is a perspective view of the second embodiment of the extrusionat section II in FIG. 1, including a first cut.

FIG. 9A is a side view of the extrusion of FIG. 9.

FIG. 10 is a perspective view of the extrusion of FIG. 9, also includinga second cut.

FIG. 10A is a side view of the extrusion of FIG. 10.

FIG. 11 is a cross sectional view of the step tube attached to abracket.

FIG. 12 is a bottom view of a mounting bracket attached to theextrusion.

FIG. 13 is a side view of an alternative embodiment.

FIG. 14 is a perspective view of the alternative embodiment of FIG. 13.

DESCRIPTION OF THE CURRENT EMBODIMENTS

A step tube constructed in accordance with a preferred embodiment of thepresent invention is shown in FIGS. 1 and 2 and generally designated 10.The step tube 10 generally includes an elongated extrusion 12, having aplurality of generally vertical ribs 14. The extrusion further includesa step portion 16, transition portions 18, 20 flanking the step portion16, and non-step portions 22, 24. The step tube is attached to a vehicle26 with a plurality of mounting brackets 28, and may include a pair ofend caps 30.

As shown in FIG. 3, the extrusion 12 is an elongated beam. The extrusionmay be comprised of aluminum, a similar alloy, a thermoplastic, or anyother suitable material. As the beam 12 is extruded, it is cut to adesired length, depending on the vehicle that it will be attached to. Asshown in FIGS. 1 and 2, the beam 12 includes a step portion 16,transition portions 18, 20 on either side of the step portion 16, andopposing non-step portions 22, 24 adjacent to the transition portions18, 20. Referring to FIG. 3, the beam 12 further includes an uppersurface 32, a front surface 34, a rear surface 36, and a lower surface38. The front surface 34 preferably includes a C-shaped slot 35 forreceiving a trim piece 52 (shown in FIG. 11). The lower 38 and rear 36surfaces preferably each include a T-shaped slot 39 for receivingattachment brackets 28.

Referring now to FIG. 4, the plurality of ribs 14 extend vertically fromthe upper surface 32 of the extrusion 12. The ribs 14 are preferablyspaced apart, and each rib has a height 40, a base 42, and an outer edge44. As shown, the height 40 of the ribs 14 decreases in each sequentialrib 14 as the ribs 14 approach the front and rear surfaces 34, 36.Alternatively, the ribs 14 may have a uniform height 40.

As shown in FIGS. 5 and 5A, the ribs 14 include a first cut 46 definingthe step portion 16. In the illustrated embodiment, the step portion 16is located in a central section of the extrusion 12 (see FIGS. 1 and 2).The first cut 46 is a cut that shaves off a portion of the height 40 ofthe ribs 14 such that the ribs 14 have a second height 48 in the stepportion 16. In one embodiment, the first 46 is a machined cut. Thesecond height 48 is preferably uniform from the front surface 34 to therear surface 36 to form a level step platform. In one embodiment, theheight 40 of the ribs 14 gradually tapers to the second height 48 withinthe transition portions 18, 20. Alternatively, the transition portions18, 20 may have a variety of desired shapes.

As shown in FIGS. 6 and 6A, the ribs 14 also may include a second cut orplurality of cuts 50. The second cuts 50 preferably extend transverselythrough the ribs 14 across the extrusion from the front surface 34 tothe rear surface 36. The second cuts 50 are preferably spaced apart in aseries of cuts throughout the step portion 16 and the transitionportions 18, 20. As shown in FIG. 6, the series of second cuts 50 have aparabolic shape as they extend transversely across the extrusion 12.Alternatively, the second cuts 50 may have a variety of desired shapesand patterns. They may be straight cuts that are perpendicular to thefirst cuts, and they may even have the formation of a logo.

Referring to FIGS. 1 and 11, the step tube may include a trim piece 52and a pair of end caps 30. The trim piece 52 is a separate decorativepart that may also be extruded from aluminum, a similar alloy, athermoplastic, or other suitable material. It also acts as a bumper toprotect the step tube 10. The trim piece 52 has a front surface 54 thatis shaped to correspond with the shape of the front surface 34 of theextrusion 12, and a rear surface 56 that includes a T-shaped protrusion58 that may be slidably coupled with the C-shaped slot 35. The end caps30 are adapted to engage the open ends 58, 60 of the extrusion, and areshaped to close off the ends. The end caps 30 may include a plurality ofvertically extending extrusions to correspond with the ribs 14.

The step tube 10 may be attached to a vehicle body by a variety ofconventional methods. FIG. 11 shows one such method, wherein at leastone mounting bracket 28 is attached at a first end 62 to the step tube10 and at a second end 64 to a vehicle body 26. The first end 62attaches to the T-shaped slots 39, with a nut 70 and bolt 72, or with aT-shaped protrusion (not shown) that may be slidably engaged with theslots 39. The second end 64 preferably attaches to the vehicle 26through slot 66 with a nut and bolt (not shown).

FIGS. 7-10 show a second embodiment of the present invention, whereinthe extrusion 12 includes a web 21 that attaches between the outer edges44 of the ribs 14, and encloses the ribs 14. As shown in FIG. 8, theprofile of the extrusion 12 is the same as the first embodiment, butfurther including the web 21. FIGS. 9 and 9A show the extrusion 12 withthe web 21, further including a first cut 46. The cut 46 is identical tothe first cut 46 of the first embodiment, however, in this embodiment,the first cut 46 removes a portion of the web 21 along with portions ofthe ribs 14. The transition portions 18, 20 and the step portion 16 arethe same as in the first embodiment. FIG. 10 additionally shows thesecond cut 15 as a series of cuts identical to those of the firstembodiment. The end portions 22, 24 continue to include the web 21 afterthe cuts 46, 50 have been made.

Another embodiment of the invention is shown in FIGS. 13 and 14. In thisembodiment, the step tube includes a plurality of step portions 16. Asshown in FIGS. 13 and 14, there are two step portions 16. The stepportions 16 generally include first and second cuts similar to thatdisclose above. As shown, the second cuts 50 are perpendicular to thefirst cuts 46. The cuts of each step portion 16 may vary in height anddesign. In general, the multiple step portions coincide in location withfront and rear doors of the vehicle and possibly a cargo bed. Of course,this embodiment may also include the web 21 of the second disclosedembodiment.

Manufacture of the present invention requires the steps of a) extrudingan elongated beam having a plurality of vertically extending ribs; b)cutting down the height of the ribs in a step portion of the beam todefine a step platform; and c) attaching the beam to a vehicle body. Thebeam may be extruded such that it has the profile shown in FIG. 4, oralternatively the profile of FIG. 8. Step b) preferably includes thefirst cut 46, followed by the second cut(s) 50. The first and secondcuts may be machined cuts that are performed in an automated process.Step c) may include attaching the beam to a vehicle with the mountingbrackets 28, as shown in FIGS. 1 and 11. The brackets are attached at afirst end 62 to the beam, and at a second end 64 to the vehicle body 26.The trim piece 52 can be slidably engaged in the slot 35.

The above descriptions are those of current embodiments of theinvention. Various alterations and changes can be made without departingfrom the spirit and broader aspects of the invention, which are to beinterpreted in accordance with the principles of patent law includingthe Doctrine of Equivalents.

1-14. (canceled)
 15. A vehicle step tube comprising: an elongated steptube body having a top portion defining a step area and a side portionbelow said top portion; and a trim piece supported by said side portion,said trim piece located below said top portion.